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XRT79L71
PRELIMINARY
69
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
The Transmit Overhead Data Input Interface block
The Transmit LAPD Controller block
The Transmit FEAC Controller block
The Transmit DS3 Framer block
The Transmit DS3 LIU Interface block
4.2.1
TRANSMIT PAYLOAD DATA INPUT INTERFACE BLOCK
The Transmit Payload Data Input Interface block is the very first functional block within the Transmit Direction
of the XRT79L71 that we will discuss for Clear-Channel Framer Applications.
illustration of the Transmit Direction circuitry whenever the XRT79L71 has been configured to operate in the
DS3 Clear-Channel Framer Mode, with the Transmit Payload Data Input Interface block highlighted.
The purpose of the Transmit Payload Data Input Interface block is to accept payload data from some system-
side or up-stream source and to pass this payload data along to the Transmit DS3 Framer block that will
ultimately map this payload data into the payload bits within each outbound DS3 frame.
In order to accomplish this, the Transmit Payload Data Input Interface block has numerous input and output
pins. Table 13 presents a list and a brief definition of each of these pins.
FIGURE 29. ILLUSTRATION OF THE FUNCTIONAL BLOCK DIAGRAM OF THE TRANSMIT DIRECTION CIRCUITRY, WHEN
THE
XRT79L71 HAS BEEN CONFIGURED TO OPERATE IN THE DS3 CLEAR-CHANNEL FRAMER MODE (WITH THE
TRANSMIT PAYLOAD DATA INPUT INTERFACE BLOCK HIGHLIGHTED
Transmit
Payload Data
Input
Interface
Block
Transmit
Payload Data
Input
Interface
Block
Transmit
DS3/E3
Framer
Block
Transmit
DS3/E3
Framer
Block
Tranmit
DS3/E3
LIU Block
Tranmit
DS3/E3
LIU Block
TxSer
TxNib[3:0]
TxInClk
TRING
TTIP
Transmit
Overhead Data
Input Interface
Block
Transmit
Overhead Data
Input Interface
Block
TxOHClk
TxOHIns
TxOHInd
TxOH
TxOHEnable
TxOHFrame
TxNibClk
TxFrame
Tx LAPD
Controller
Block
Tx LAPD
Controller
Block
From Microprocessor
Interface Block
Tx LAPD
Buffer
(90 Bytes)
Tx LAPD
Buffer
(90 Bytes)
Tx FEAC
Processor
Block
Tx FEAC
Processor
Block